import pygame.font

class Button():
    def __init__(self,ai_settings,screen,msg):
        self.screen=screen
        self.screen_rect=screen.get_rect()

        self.width,self.height=200,50
        self.button_color=(0,255,0)
        self.text_color=(255,255,255)
        self.font=pygame.font.SysFont(None,48)

        self.rect=pygame.Rect(0,0,self.width,self.height)
        self.rect.center=self.screen_rect.center

        self.prep_msg(msg)

    def prep_msg(self, msg):
        """将msg渲染为图像，并使其在按钮上居中"""
        self.msg_image = self.font.render(msg, True, self.text_color,
        self.button_color)
        self.msg_image_rect = self.msg_image.get_rect()
        self.msg_image_rect.center = self.rect.center

    def draw_button(self):
        self.screen.fill(self.button_color,self.rect)
        self.screen.blit(self.msg_image,self.msg_image_rect)
